Double lift single screw jack



June 14, 1932. J. A. MORRISON I DOUBLE LIFT SINGLE SCREW JACK i FiledMarch 28, 1931 ad I; 3

3 .JA. Mrrzkap fl WM 7 5. 0 IW 2 2 .9. wax w height, at which PatentedJune 14, 1932 UNITED STATES some a monnrson', or WARREN, onro DOUBLELIFT SINGLE SCREW JACK Application filed March 28, 1931. Serial No.526,040.

The invention relates to lifting jacks such as are used for automobiles,trucks and other vehicles, and more particularly to a double lift jackprovided with a single screw.

j J acks' of the type to which the invention peitains comprise twotubular lifting members adapted to be operated by a single liftingscrew, one lifting member being raised, by means of the screw, to apredetermined point it is automatically locked to the other liftingmember, which has been held against movement during this time, thesecond lifting member being-then automatically brought into engagementwith the 5 lifting screw and raised to the limit of its movement,carrying with it the first lifting member which is locked thereto inextended position.

I am aware that attempts have been made in the past to produce acks ofthis type, and that patents have been obtained upon such jacks, but noneof the jacks so produced or patented have proven commercially practicaldue to the locking means, for locking the two lifting members together,being insuflicient, and incapable of holding up under use. For thisreason jacks of this type have never come into commercial use. 7

The object of the present improvement is to provide a practical, durableand efficient locking means for automatically locking the two liftingmemberstogether at the desired point.

A further object is to provide such a looking means in the form of acollar which surrounds the inner lifting member and rests upon the upperend of the outer lifting member, means being provided upon said collarfor engaging the lower portion of the inner member when it is raised toa predetermined height.

The above, together with other objects which will be readily apparent,from the ac- 3 companying drawing and the following detail description,or which will be hereinafter pointed out, may be attained byconstructing the jack in the manner illustrated in the accompanyingdrawing, in which Figure is a vertical sectional view of the improvedjack, showing the same in the lowered or collapsed position;

Fig. 2, a plan view of the improved locking collar;

Fig. 3, a top plan view of the housing within which the lifting membersare normally contained;

Fig. 4, a sectional view of the upper portion of the housing takensubstantially on the line inner lifting member with the locking collarin operative position, parts'being broken away for the purpose ofillustration; and

Fig. 6, a vertical sectional view-of the upper portion of the outerlifting member, and the lower portion of the inner lifting member, 7locked in extended position by the improved locking collar.

Similar numerals refer to similar parts throughout the drawing.

The jack may include the tubular housing 10, mounted upon the hollowbase 11, which forms a gear housing for the bevel gear 12 and the bevelpinion 13 which meshes therewith. The gear 12 is axially fixed upon thevertical screw 14 and is mounted upon the so thrust bearing 15, of anysuitable or desirable construction, located in the bottom of the. gearhousing 11, and adapted to take the thrust of said screw under load.

The bevel pinion 13 is fixed upon the inner at end of the short shaft16, which is journaled in the inclined bearing 17 and provided at itsouter end with the usual socket or handle engaging portion 19 forengagement by the ordinary operating handle such as is commonly used forraising and lowering 'acks of this general type.

The tubular outer lifting member 20, is mounted for vertical movementwithin the housing 10, and is provided at its lower end with the nutportion 21, normally receiving the u-nthreadedportion 22 of the screw14, when the jack is in the lowered position, as illustrated in Fig. 1of the drawing.

For the purpose of preventing rotation of 1 the tubular member 20, whenthe same is moved vertically within the housing 10, studs 23 may belined in the lower portion of said tubular n'icmber for slidingengagement in the vertical grooves 21 formed in the inner wall of thehousing 10.

The inner lilting member 25 is also of tubular form and is slid ablewithin the outer member 20, being provided, at its ower end, with thenut portion 26 normally engaged by the screw .14. Apair of diametricallyopposed, longitudinal grooves 27 are formed in the inner tube 25, one ofthese grooves receiving the stud 28 projecting inward from the up perportion of the outer tubular member 20, to prevent relative rotation ofthe inner and outer lifting members.

The improved locking collar, which forms the principal feature of theinvention, indicated by the numeral 29, and is of substantially the someinner and outer diamcters as the outer lifting member 20, upon the upperend of whi h the collar is located, surrounding the inner lifting member25.

Studs 30 are diametrically located in the collar 29, and arranged to benormally received in the oppositely inclined grooves 31, formed in theinterior of the upper portion of the housing 10. Inwardly disposed lugs32., preferably equal in height to the collar, and tapered at theirinner ends as shown in the drawing. are formed upon the interior of.

the collar and normally received within the vertical grooves 27 in theinner lifting mcm her. These lugs, as well as the studs 30, may beintegral parts of the collar, which, for the purpose of strength. ispreferably in the form of a drop forging.

Each of the grooves 27, in the inner lifting member, is provided nearits lower end with an angular enlargement 33, arranged to receive thelugs 32, when the collar is turned to locking position, as illustratedin Fig. 5. Any suitable form of lifting cap, as shown at 34, may beprovided upon the upper end of the inner lifting member, for engagementwith the axle, spring, or other part of the vehicle to be lifted.

In the operation of the jack, assuming that the parts are in the normal,or lowered, position, as best shown in Fig. 1, the usual operatinghandle is connected to the socket 19, in customary manner, and rotatedin the proper direction, whereby through the pinion 13 and gear 12 thescrew 14 is rotated.

The outer lifting member 20 at first remains stationary, as the nut 21thereof is not engagcd by the screw, but the nut 26 of the inner liftingmember being in engagement with the screw will cause said inner liftingmember to ride upward upon the screw.

As the inner lifting member is raised to a point where the stud 28 ofthe outer lifting member is engaged by the shoulder 35 at the lower endof the corresponding groove 27, the

outer lifting member will begin to rise with the inner member, movingthe nut 21 thereof into engagement with the screw 14.

At the same time that the outer lifting member starts to rise, thecollar 29 will be pushed upward thereby, and will be rotated by means ofthe lugs 30 passing upward through the inclined grooves 31 in thehousing, moving the internal lugs 32 of the collar into the angularenlargements 33 in the lower portions of'the inner lifting member, thuslocking the inner lifting member in extended position upon the upper endof the outer lifting member, before the nut 26 of the inner memberpasses upward out of engagement with the screw.

Further rotation of the screw will cause the outer lifting member tocontinue to rise until the studs 23 thereon contact with the upper ends36 of the grooves 24, the inner member being carried upward in extendedposition upon the upper end of the outer lifting member.

In order to lower the jack the screw is 1'0- tated in the oppositedirection, moving the nut 21 of the outer member downward until thestuds 30 of the collar 29 are again received in the inclined grooves 31of the housing, rotating said collar to move the lugs 32 thereof out ofthe enlarged angular pockets 33 and back into the grooves 27 of theinner lifting member, while at the same time the nut 26 of the innerlifting member is again moved into engagement with the screw 1%.

Immediately thereafter the nut 21 of the outer lifting member will bemoved downward out of engagement with the screw, the outer liftingmember returning to the position shown in Fig. 1. The inner liftingmemher will then continue to descend until it also returns to theposition shown in Fig. 1.

I claim:

1. A lifting jack including a housing, a screw within the housing, meansfor rotating the screw, a pair of tubular lifting members normallytelescoped within the housing, nuts upon said lifting members forengagement with the screw, a collar at the upper end of the outerlifting member, and means for automatically locking said collar to theinner lifting member when said inner lifting member has been raised to apredetermined point.

2. A lifting jack including a housing, a screw within the housing, meansfor rotating the screw, a pair of tubular lifting members normallytelescoped within the housing, nuts upon said lifting members forengagement with the screw, a rotatable collar at the upper end of theouter lifting member, and means for automatically rotating said collarfor locking said collar to the inner lifting member when said innerlifting member has been raised to a predetermined point.

3. A lifting jack including a housing, a screw within the housing, meansfor rotating the screw, a pair of tubular lifting members normallytelescoped within the housing, nuts upon said lifting members forengagement with the screw, a collar at the upper end of the outerlifting member, and means upon the collar and housing for automaticallylocking said collar to the inner lifting member when said inner liftingmember has been raised to a predetermined point.

4-. A lifting jack including a housing a screw within the housing, meansfor rotating the screw, a pair of tubular lifting members normallytelcscopcd within the housing, nuts upon said lifting members forengagement with the screw, a rotatable collar at the upper end of theouter lifting member, and means upon the collar and housing forautomatically rotating said collar for locking said collar to the innerlifting member when said inner lifting member has been raised to apredetermined point.

ii. A lifting jack including a housing, a screw within the housing,means for rotating the screw, a pair of tubular lifting members normallytelescoped within the housing, nuts upon said lifting members forengagement with the screw, a rotatable collar at the upper end of theouter lifting member, and coacting studs and inclined grooves in thecollar and housing for automatically rotatthe collar for locking thecollar to the inner lifting member when said inner lifting member hasbeen raised. to a predetermined point.

A lifting jack including a housing having inclined grooves therein, ascrew within the housing, means for rotating the screw, a pair oftubular lifting members normally telescoped within the housing, nutsupon said lifting members for engagement with the s ew, a rotatablecollar at the upper end or the outer lifting member, and studs uponcollar for engagement with the inclined s in the housing forautomatically the collar for locking the collar to ier lifting memberwhen said inner member has been raised to a predeliftingjaclr includinga housing, a

screwwiuain the housing, means for rotatthe screw a pair of tubularlifting memnuts upon said lifting members for engagemeat with the screw,the inner lifting memb ing longitudinal grooves provided 'ar portionsnear their lower ends,

hers normally tale-scoped within the housing,

ing the screw, a pair of tubular lifting members normally telescopedwithin the housing, nuts upon said lifting members for engage ment withthe screw, the inner lifting member having longitudinal grooves providedwith angular portions near their lower ends, a rotatable collar at theupper end of the outer lifting member, lugs upon said collar forengagement with said grooves, and means upon the collar and housing forautomatically rotating said collar to move the lugs into the angularportions of the grooves when the inner lifting member has been raised toa predetermined point.

9. A lifting jack including a housing, a screw within the housing, meansfor rotating the screw, a pair of tubular lifting members normallytelescoped within the housing, nuts upon said lifting members forengagement with the screw, the inner lifting member having longitudinalgrooves provided with angular portions near their lower ends, arotatable collar at the upper end of the outer lifting member, lugs uponsaid collar for engagement with said grooves, and coacting studs andinclined grooves in the collar and housing for automatically rotatingsaid collar to move the lugs into the angular portions of the grooveswhen the inner lifting member has been raised to a predetermined point.

In testimony that I claim the above, I have hereunto subscribed my name.

JOHN A. MORRISON.

le collar at the upper end of the I

